Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149 Münster, Germany.
J Am Chem Soc. 2021 May 26;143(20):7648-7654. doi: 10.1021/jacs.1c03492. Epub 2021 May 11.
Herein, we describe the formation of quaternary carbon centers with excellent diastereoselectivity via a strain-release protocol. An organometallic species is generated by Cp*Rh(III)-catalyzed C-H activation, which is then coupled with strained bicyclobutanes (BCBs) and a prochiral carbon electrophile in a three-component reaction. This work illustrates a rare example of BCBs in transition metal catalysis and demonstrates their broad potential to access novel reaction pathways. The method developed exhibits ample functional group tolerance, and the products can be further transformed into valuable α-quaternary β-lactones. Preliminary mechanistic investigations suggest a twofold C-C bond cleavage sequence involving σ-bond insertion and an ensuing β-carbon elimination event.
在此，我们通过应变释放策略描述了具有优异非对映选择性的季碳原子中心的形成。通过 Cp*Rh(III)催化的 C-H 活化生成有机金属物种，然后在三组分反应中与张力双环丁烷 (BCB) 和手性亲电碳试剂偶联。这项工作说明了 BCB 在过渡金属催化中的一个罕见实例，并证明了它们在获得新反应途径方面的广泛潜力。所开发的方法表现出对大量官能团的耐受性，并且产物可以进一步转化为有价值的α-季碳β-内酰胺。初步的机理研究表明涉及σ键插入和随后的β-碳原子消除事件的双重 C-C 键断裂序列。
